In a well-developed modern society, people often eat too many garbage foods, however spend little time in exercises. Therefore, most people have an excessive weight. Because the weight has a great concern with one's physical condition, some persons measure their weight daily in order to control it within a suitable range. However, most weighing scales, including the so-called handy weighing scales, are not convenient to be carried with. Since jogging is a sport suitable for all ages, and is helpful to the health, persons may carry a counter to count the number of steps while jogging. However, it is not convenient to hold a counter in hand when jogging. If one forgets to carry a counter, he will be unable to count the number of steps.